Prior art drive tubes have been used in dental equipment to finely adjust the size, shape and positioning of orthodontic appliances. The prior art provides a number of devices for adjusting orthodontic appliances. Prior art devices include the Orthodontic Expansion Screw, U.S. Pat. No. 4,347,054, from Hans-Joachim Kraus and Berthold Walter, both of Germany. U.S. Pat. No. 4,347,054 discloses an adjustment device having two screw bodies displaceable through a screw spindle. The screw spindle has sections of counter rotating threads engaging threaded bores in opposed sections.
Prior art also provides an Orthodontic Spreader, U.S. Pat. No. 4,482,318, from Rolf Forster, also of Germany. The Orthodontic Spreader comprises an actuating screw for moving pressure transmitting nuts in opposite directions. Slideably mounted guide rods are mounted in both pressure transmitting nuts.
Some prior art adjustment devices are too large for some applications. Also, prior art drive tubes do not maintain solid contact with a bite block mounting and become unattached and move during adjustment. Prior art drive tubes have small diameter screw heads making adjustment difficult. Universal Dynamics, Inc. of Minneapolis, Minn. has been providing drive tubes for the orthodontic industry for a number of years, the latest improvements being part of the apparatus of the invention.
It is therefore the motive of the invention to provide a drive tube with a large diameter screw head facilitating adjustment with a roughened surface that provides a strong attachment to a bite block.